regex.tcc

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// class template regex -*- C++ -*-

// Copyright (C) 2013-2014 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/**
 *  @file bits/regex.tcc
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{regex}
 */

// See below __regex_algo_impl to get what this is talking about. The default
// value 1 indicated a conservative optimization without giving up worst case
// performance.
#ifndef _GLIBCXX_REGEX_DFS_QUANTIFIERS_LIMIT
#define _GLIBCXX_REGEX_DFS_QUANTIFIERS_LIMIT 1
#endif

namespace std _GLIBCXX_VISIBILITY(default)
{
namespace __detail
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  // Result of merging regex_match and regex_search.
  //
  // __policy now can be _S_auto (auto dispatch) and _S_alternate (use
  // the other one if possible, for test purpose).
  //
  // That __match_mode is true means regex_match, else regex_search.
  template<typename _BiIter, typename _Alloc,
       typename _CharT, typename _TraitsT,
       _RegexExecutorPolicy __policy,
       bool __match_mode>
    bool
    __regex_algo_impl(_BiIter                              __s,
              _BiIter                              __e,
              match_results<_BiIter, _Alloc>&      __m,
              const basic_regex<_CharT, _TraitsT>& __re,
              regex_constants::match_flag_type     __flags)
    {
      if (__re._M_automaton == nullptr)
    return false;

      typename match_results<_BiIter, _Alloc>::_Base_type& __res = __m;
      __res.resize(__re._M_automaton->_M_sub_count() + 2);
      for (auto& __it : __res)
    __it.matched = false;

      // This function decide which executor to use under given circumstances.
      // The _S_auto policy now is the following: if a NFA has no
      // back-references and has more than _GLIBCXX_REGEX_DFS_QUANTIFIERS_LIMIT
      // quantifiers (*, +, ?), the BFS executor will be used, other wise
      // DFS executor. This is because DFS executor has a exponential upper
      // bound, but better best-case performace. Meanwhile, BFS executor can
      // effectively prevent from exponential-long time matching (which must
      // contains many quantifiers), but it's slower in average.
      //
      // For simple regex, BFS executor could be 2 or more times slower than
      // DFS executor.
      //
      // Of course, BFS executor cannot handle back-references.
      bool __ret;
      if (!__re._M_automaton->_M_has_backref
      && (__policy == _RegexExecutorPolicy::_S_alternate
          || __re._M_automaton->_M_quant_count
        > _GLIBCXX_REGEX_DFS_QUANTIFIERS_LIMIT))
    {
      _Executor<_BiIter, _Alloc, _TraitsT, false>
        __executor(__s, __e, __m, __re, __flags);
      if (__match_mode)
        __ret = __executor._M_match();
      else
        __ret = __executor._M_search();
    }
      else
    {
      _Executor<_BiIter, _Alloc, _TraitsT, true>
        __executor(__s, __e, __m, __re, __flags);
      if (__match_mode)
        __ret = __executor._M_match();
      else
        __ret = __executor._M_search();
    }
      if (__ret)
    {
      for (auto __it : __res)
        if (!__it.matched)
          __it.first = __it.second = __e;
      auto& __pre = __res[__res.size()-2];
      auto& __suf = __res[__res.size()-1];
      if (__match_mode)
        {
          __pre.matched = false;
          __pre.first = __s;
          __pre.second = __s;
          __suf.matched = false;
          __suf.first = __e;
          __suf.second = __e;
        }
      else
        {
          __pre.first = __s;
          __pre.second = __res[0].first;
          __pre.matched = (__pre.first != __pre.second);
          __suf.first = __res[0].second;
          __suf.second = __e;
          __suf.matched = (__suf.first != __suf.second);
        }
      if (__re.flags() & regex_constants::nosubs)
        __res.resize(3);
    }
      return __ret;
    }

_GLIBCXX_END_NAMESPACE_VERSION
}

_GLIBCXX_BEGIN_NAMESPACE_VERSION

  template<typename _Ch_type>
  template<typename _Fwd_iter>
    typename regex_traits<_Ch_type>::string_type
    regex_traits<_Ch_type>::
    lookup_collatename(_Fwd_iter __first, _Fwd_iter __last) const
    {
      typedef std::ctype<char_type> __ctype_type;
      const __ctype_type& __fctyp(use_facet<__ctype_type>(_M_locale));

      static const char* __collatenames[] =
    {
      "NUL",
      "SOH",
      "STX",
      "ETX",
      "EOT",
      "ENQ",
      "ACK",
      "alert",
      "backspace",
      "tab",
      "newline",
      "vertical-tab",
      "form-feed",
      "carriage-return",
      "SO",
      "SI",
      "DLE",
      "DC1",
      "DC2",
      "DC3",
      "DC4",
      "NAK",
      "SYN",
      "ETB",
      "CAN",
      "EM",
      "SUB",
      "ESC",
      "IS4",
      "IS3",
      "IS2",
      "IS1",
      "space",
      "exclamation-mark",
      "quotation-mark",
      "number-sign",
      "dollar-sign",
      "percent-sign",
      "ampersand",
      "apostrophe",
      "left-parenthesis",
      "right-parenthesis",
      "asterisk",
      "plus-sign",
      "comma",
      "hyphen",
      "period",
      "slash",
      "zero",
      "one",
      "two",
      "three",
      "four",
      "five",
      "six",
      "seven",
      "eight",
      "nine",
      "colon",
      "semicolon",
      "less-than-sign",
      "equals-sign",
      "greater-than-sign",
      "question-mark",
      "commercial-at",
      "A",
      "B",
      "C",
      "D",
      "E",
      "F",
      "G",
      "H",
      "I",
      "J",
      "K",
      "L",
      "M",
      "N",
      "O",
      "P",
      "Q",
      "R",
      "S",
      "T",
      "U",
      "V",
      "W",
      "X",
      "Y",
      "Z",
      "left-square-bracket",
      "backslash",
      "right-square-bracket",
      "circumflex",
      "underscore",
      "grave-accent",
      "a",
      "b",
      "c",
      "d",
      "e",
      "f",
      "g",
      "h",
      "i",
      "j",
      "k",
      "l",
      "m",
      "n",
      "o",
      "p",
      "q",
      "r",
      "s",
      "t",
      "u",
      "v",
      "w",
      "x",
      "y",
      "z",
      "left-curly-bracket",
      "vertical-line",
      "right-curly-bracket",
      "tilde",
      "DEL",
      ""
    };

      // same as boost
      //static const char* __digraphs[] =
      //  {
      //    "ae",
      //    "Ae",
      //    "AE",
      //    "ch",
      //    "Ch",
      //    "CH",
      //    "ll",
      //    "Ll",
      //    "LL",
      //    "ss",
      //    "Ss",
      //    "SS",
      //    "nj",
      //    "Nj",
      //    "NJ",
      //    "dz",
      //    "Dz",
      //    "DZ",
      //    "lj",
      //    "Lj",
      //    "LJ",
      //    ""
      //  };

      std::string __s(__last - __first, '?');
      __fctyp.narrow(__first, __last, '?', &*__s.begin());

      for (unsigned int __i = 0; *__collatenames[__i]; __i++)
    if (__s == __collatenames[__i])
      return string_type(1, __fctyp.widen(static_cast<char>(__i)));

      //for (unsigned int __i = 0; *__digraphs[__i]; __i++)
      //  {
      //    const char* __now = __digraphs[__i];
      //    if (__s == __now)
      //      {
      //    string_type ret(__s.size(), __fctyp.widen('?'));
      //    __fctyp.widen(__now, __now + 2/* ouch */, &*ret.begin());
      //    return ret;
      //      }
      //  }
      return string_type();
    }

  template<typename _Ch_type>
  template<typename _Fwd_iter>
    typename regex_traits<_Ch_type>::char_class_type
    regex_traits<_Ch_type>::
    lookup_classname(_Fwd_iter __first, _Fwd_iter __last, bool __icase) const
    {
      typedef std::ctype<char_type> __ctype_type;
      typedef std::ctype<char> __cctype_type;
      typedef const pair<const char*, char_class_type> _ClassnameEntry;
      const __ctype_type& __fctyp(use_facet<__ctype_type>(_M_locale));
      const __cctype_type& __cctyp(use_facet<__cctype_type>(_M_locale));

      static _ClassnameEntry __classnames[] =
      {
    {"d", ctype_base::digit},
    {"w", {ctype_base::alnum, _RegexMask::_S_under}},
    {"s", ctype_base::space},
    {"alnum", ctype_base::alnum},
    {"alpha", ctype_base::alpha},
    {"blank", {0, _RegexMask::_S_blank}},
    {"cntrl", ctype_base::cntrl},
    {"digit", ctype_base::digit},
    {"graph", ctype_base::graph},
    {"lower", ctype_base::lower},
    {"print", ctype_base::print},
    {"punct", ctype_base::punct},
    {"space", ctype_base::space},
    {"upper", ctype_base::upper},
    {"xdigit", ctype_base::xdigit},
      };

      std::string __s(__last - __first, '?');
      __fctyp.narrow(__first, __last, '?', &__s[0]);
      __cctyp.tolower(&*__s.begin(), &*__s.begin() + __s.size());
      for (_ClassnameEntry* __it = __classnames;
       __it < *(&__classnames + 1);
       ++__it)
    {
      if (__s == __it->first)
        {
          if (__icase
          && ((__it->second
               & (ctype_base::lower | ctype_base::upper)) != 0))
        return ctype_base::alpha;
          return __it->second;
        }
    }
      return 0;
    }

  template<typename _Ch_type>
    bool
    regex_traits<_Ch_type>::
    isctype(_Ch_type __c, char_class_type __f) const
    {
      typedef std::ctype<char_type> __ctype_type;
      const __ctype_type& __fctyp(use_facet<__ctype_type>(_M_locale));

      return __fctyp.is(__f._M_base, __c)
    // [[:w:]]
    || ((__f._M_extended & _RegexMask::_S_under)
        && __c == __fctyp.widen('_'))
    // [[:blank:]]
    || ((__f._M_extended & _RegexMask::_S_blank)
        && (__c == __fctyp.widen(' ')
        || __c == __fctyp.widen('\t')));
    }

  template<typename _Ch_type>
    int
    regex_traits<_Ch_type>::
    value(_Ch_type __ch, int __radix) const
    {
      std::basic_istringstream<char_type> __is(string_type(1, __ch));
      long __v;
      if (__radix == 8)
    __is >> std::oct;
      else if (__radix == 16)
    __is >> std::hex;
      __is >> __v;
      return __is.fail() ? -1 : __v;
    }

  template<typename _Bi_iter, typename _Alloc>
  template<typename _Out_iter>
    _Out_iter match_results<_Bi_iter, _Alloc>::
    format(_Out_iter __out,
       const match_results<_Bi_iter, _Alloc>::char_type* __fmt_first,
       const match_results<_Bi_iter, _Alloc>::char_type* __fmt_last,
       match_flag_type __flags) const
    {
      _GLIBCXX_DEBUG_ASSERT( ready() );
      regex_traits<char_type> __traits;
      typedef std::ctype<char_type> __ctype_type;
      const __ctype_type&
    __fctyp(use_facet<__ctype_type>(__traits.getloc()));

      auto __output = [&](size_t __idx)
    {
      auto& __sub = _Base_type::operator[](__idx);
      if (__sub.matched)
        std::copy(__sub.first, __sub.second, __out);
    };

      if (__flags & regex_constants::format_sed)
    {
      for (; __fmt_first != __fmt_last;)
        if (*__fmt_first == '&')
          {
        __output(0);
        ++__fmt_first;
          }
        else if (*__fmt_first == '\\')
          {
        if (++__fmt_first != __fmt_last
            && __fctyp.is(__ctype_type::digit, *__fmt_first))
          __output(__traits.value(*__fmt_first++, 10));
        else
          *__out++ = '\\';
          }
        else
          *__out++ = *__fmt_first++;
    }
      else
    {
      while (1)
        {
          auto __next = std::find(__fmt_first, __fmt_last, '$');
          if (__next == __fmt_last)
        break;

          std::copy(__fmt_first, __next, __out);

          auto __eat = [&](char __ch) -> bool
        {
          if (*__next == __ch)
            {
              ++__next;
              return true;
            }
          return false;
        };

          if (++__next == __fmt_last)
        *__out++ = '$';
          else if (__eat('$'))
        *__out++ = '$';
          else if (__eat('&'))
        __output(0);
          else if (__eat('`'))
        __output(_Base_type::size()-2);
          else if (__eat('\''))
        __output(_Base_type::size()-1);
          else if (__fctyp.is(__ctype_type::digit, *__next))
        {
          long __num = __traits.value(*__next, 10);
          if (++__next != __fmt_last
              && __fctyp.is(__ctype_type::digit, *__next))
            {
              __num *= 10;
              __num += __traits.value(*__next++, 10);
            }
          if (0 <= __num && __num < this->size())
            __output(__num);
        }
          else
        *__out++ = '$';
          __fmt_first = __next;
        }
      std::copy(__fmt_first, __fmt_last, __out);
    }
      return __out;
    }

  template<typename _Out_iter, typename _Bi_iter,
       typename _Rx_traits, typename _Ch_type>
    _Out_iter
    regex_replace(_Out_iter __out, _Bi_iter __first, _Bi_iter __last,
          const basic_regex<_Ch_type, _Rx_traits>& __e,
          const _Ch_type* __fmt,
          regex_constants::match_flag_type __flags)
    {
      typedef regex_iterator<_Bi_iter, _Ch_type, _Rx_traits> _IterT;
      _IterT __i(__first, __last, __e, __flags);
      _IterT __end;
      if (__i == __end)
    {
      if (!(__flags & regex_constants::format_no_copy))
        std::copy(__first, __last, __out);
    }
      else
    {
      sub_match<_Bi_iter> __last;
      auto __len = char_traits<_Ch_type>::length(__fmt);
      for (; __i != __end; ++__i)
        {
          if (!(__flags & regex_constants::format_no_copy))
        std::copy(__i->prefix().first, __i->prefix().second, __out);
          __out = __i->format(__out, __fmt, __fmt + __len, __flags);
          __last = __i->suffix();
          if (__flags & regex_constants::format_first_only)
        break;
        }
      if (!(__flags & regex_constants::format_no_copy))
        std::copy(__last.first, __last.second, __out);
    }
      return __out;
    }

  template<typename _Bi_iter,
       typename _Ch_type,
       typename _Rx_traits>
    bool
    regex_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
    operator==(const regex_iterator& __rhs) const
    {
      return (_M_match.empty() && __rhs._M_match.empty())
    || (_M_begin == __rhs._M_begin
        && _M_end == __rhs._M_end
        && _M_pregex == __rhs._M_pregex
        && _M_flags == __rhs._M_flags
        && _M_match[0] == __rhs._M_match[0]);
    }

  template<typename _Bi_iter,
       typename _Ch_type,
       typename _Rx_traits>
    regex_iterator<_Bi_iter, _Ch_type, _Rx_traits>&
    regex_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
    operator++()
    {
      // In all cases in which the call to regex_search returns true,
      // match.prefix().first shall be equal to the previous value of
      // match[0].second, and for each index i in the half-open range
      // [0, match.size()) for which match[i].matched is true,
      // match[i].position() shall return distance(begin, match[i].first).
      // [28.12.1.4.5]
      if (_M_match[0].matched)
    {
      auto __start = _M_match[0].second;
      auto __prefix_first = _M_match[0].second;
      if (_M_match[0].first == _M_match[0].second)
        {
          if (__start == _M_end)
        {
          _M_match = value_type();
          return *this;
        }
          else
        {
          if (regex_search(__start, _M_end, _M_match, *_M_pregex,
                   _M_flags
                   | regex_constants::match_not_null
                   | regex_constants::match_continuous))
            {
              _GLIBCXX_DEBUG_ASSERT(_M_match[0].matched);
              _M_match.at(_M_match.size()).first = __prefix_first;
              _M_match._M_in_iterator = true;
              _M_match._M_begin = _M_begin;
              return *this;
            }
          else
            ++__start;
        }
        }
      _M_flags |= regex_constants::match_prev_avail;
      if (regex_search(__start, _M_end, _M_match, *_M_pregex, _M_flags))
        {
          _GLIBCXX_DEBUG_ASSERT(_M_match[0].matched);
          _M_match.at(_M_match.size()).first = __prefix_first;
          _M_match._M_in_iterator = true;
          _M_match._M_begin = _M_begin;
        }
      else
        _M_match = value_type();
    }
      return *this;
    }

  template<typename _Bi_iter,
       typename _Ch_type,
       typename _Rx_traits>
    regex_token_iterator<_Bi_iter, _Ch_type, _Rx_traits>&
    regex_token_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
    operator=(const regex_token_iterator& __rhs)
    {
      _M_position = __rhs._M_position;
      _M_subs = __rhs._M_subs;
      _M_n = __rhs._M_n;
      _M_result = __rhs._M_result;
      _M_suffix = __rhs._M_suffix;
      _M_has_m1 = __rhs._M_has_m1;
      if (__rhs._M_result == &__rhs._M_suffix)
    _M_result = &_M_suffix;
      return *this;
    }

  template<typename _Bi_iter,
       typename _Ch_type,
       typename _Rx_traits>
    bool
    regex_token_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
    operator==(const regex_token_iterator& __rhs) const
    {
      if (_M_end_of_seq() && __rhs._M_end_of_seq())
    return true;
      if (_M_suffix.matched && __rhs._M_suffix.matched
      && _M_suffix == __rhs._M_suffix)
    return true;
      if (_M_end_of_seq() || _M_suffix.matched
      || __rhs._M_end_of_seq() || __rhs._M_suffix.matched)
    return false;
      return _M_position == __rhs._M_position
    && _M_n == __rhs._M_n
    && _M_subs == __rhs._M_subs;
    }

  template<typename _Bi_iter,
       typename _Ch_type,
       typename _Rx_traits>
    regex_token_iterator<_Bi_iter, _Ch_type, _Rx_traits>&
    regex_token_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
    operator++()
    {
      _Position __prev = _M_position;
      if (_M_suffix.matched)
    *this = regex_token_iterator();
      else if (_M_n + 1 < _M_subs.size())
    {
      _M_n++;
      _M_result = &_M_current_match();
    }
      else
    {
      _M_n = 0;
      ++_M_position;
      if (_M_position != _Position())
        _M_result = &_M_current_match();
      else if (_M_has_m1 && __prev->suffix().length() != 0)
        {
          _M_suffix.matched = true;
          _M_suffix.first = __prev->suffix().first;
          _M_suffix.second = __prev->suffix().second;
          _M_result = &_M_suffix;
        }
      else
        *this = regex_token_iterator();
    }
      return *this;
    }

  template<typename _Bi_iter,
       typename _Ch_type,
       typename _Rx_traits>
    void
    regex_token_iterator<_Bi_iter, _Ch_type, _Rx_traits>::
    _M_init(_Bi_iter __a, _Bi_iter __b)
    {
      _M_has_m1 = false;
      for (auto __it : _M_subs)
    if (__it == -1)
      {
        _M_has_m1 = true;
        break;
      }
      if (_M_position != _Position())
    _M_result = &_M_current_match();
      else if (_M_has_m1)
    {
      _M_suffix.matched = true;
      _M_suffix.first = __a;
      _M_suffix.second = __b;
      _M_result = &_M_suffix;
    }
      else
    _M_result = nullptr;
    }

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace